<!DOCTYPE html>
<html lang="en">

    <head>
        <meta charset="UTF-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Document</title>
    </head>

    <body>
        <style>
            .trail {
                /* className for the trail elements */
                position: absolute;
                height: 6px;
                width: 6px;
                border-radius: 3px;
                background: teal;
            }

            body {
                height: 300px;
            }
        </style>

        <script>
        // Your code here.
        </script>
    </body>

</html>